I've thought about Hot Rod's options here, and he also could have yelled, but yelling could've given Megatron precisely the distraction he was looking for. Shooting would have been the correct choice, but Hot Rod chose tackle. I'm willing to admit that Hot Rod was an idiot there.
But the thing is, Hot Rod is supposed to be a child, a teenager, to be precise. He acted without thinking when he opened fire on the shuttle (good call), and he acted without thinking when he tried to tackle Megatron (bad call).
People crap on Hot Rod for touching the Matrix, as if this was the sole reason why they couldn't have Ultra Magnus as New Leader instead of Rodimus Prime, but Hot Rod respectfully handed the Matrix to Ultra Magnus, who he accepted as his New Leader.
Bobby Roberts has mentioned before that the split-up adventures with the two shuttles seems to have no purpose in the story, but I think it works as a comparison between Hot Rod and Ultra Magnus as leader.
Ultra Magnus ordered Blurr to get the Dinobots on the shuttle, but Blurr couldn't do it, because the Dinobots are too stubborn. So Ultra Magnus ordered Kup and Hot Rod to take over for Blurr, while everyone else gets on a different shuttle. One could infer that Ultra Magnus was willing to let Kup and Hot Rod (the two most useless Autobots) die, if they couldn't get the job done and the Dinobots could be deemed a lost cause. But then Hot Rod made a lasso and corralled Grimlock, and got his shuttle launched first. And Ultra Magnus launched his shuttle before Arcee was aboard. Good thing she jumped/Springer caught her, otherwise Ultra Magnus would've looked pretty bad.
In the air, Hot Rod's shuttle got pounded by Galvatron until it went down. Ultra Magnus: "I can't deal with that right now." That is sooo not the response of a leader. But he did manage to buy some time by crashing on his own planet.
On his planet, Hot Rod fought his way past robo-vines and robo-piranhas, to find Kup defeated by a robo-squid, which Hot Rod defeated using cleverness since the robo-squid was overpowering. Then they got arrested and Hot Rod pretty much busted his way out of jail before Grimlock arrived to seal the deal.
Ultra Magnus meanwhile, got another visit from Galvatron, and Magnus managed to save his crew by burying them, to face Galvatron alone. And then like an idiot, he whipped out the Matrix and tried to use it to nuke Galvatron, because this must be the Autobots Darkest Hour, even though earlier in the film they had just planned to try using the Matrix on Unicron, who was still out there. Magnus backed into a corner = The end of the world. Magnus: "WTF Optimus? You told me this would work." No, Optimus didn't. Magnus told Optimus he wasn't worthy. Optimus said that he knew that Magnus wasn't worthy, and neither was he. But legend says that one day a Chosen One will come along, and he will be worthy, and he will Light their Darkest Hour. Ultra Magnus (despite his earlier reluctance, and his pounding string of failures) ended up thinking the Chosen One was him. And then he got himself blown to bits. Oops.
Then Hot Rod comes along and saves Ultra Magnus' crew from the Junkions by making peace with them, using the technique that didn't work for Kup previously.
Then Hot Rod leads everyone to go after the lost Matrix and try to stop Unicron, and he gets separated from the group and winds up alone with Galvatron, and unafraid, he fights Galvatron better than anyone has since Galvatron showed up and started powning Autobots and Decepticons left and right, because Hot Rod's dodging and using hit-and-run tactics to frustrate his stronger opponent. And remember, Hot Rod is still a child at this point. A teenager. And he's putting up a better fight than Ultra Magnus did. That's why I say Hot Rod is an idiot, but he doesn't suck.