When Cheetor injects the anti-virus into Optimus, his hand twists so much to the side, that it passes through his armor. Then, his fist "slips off" the anti-virus vial, which miraculously continues to float in mid-air. When the vial drops to the floor, Cheetor still hasn't opened his hand.
Rhinox claims that when Scorponok's gadget explodes, it will wipe out everyone within "sprinting distance". Yet when it does, both Scorponok and Megatron are at ground zero, and they survive the incident. Everyone else manages to run away.