I think it would really depend on what the blinds are in relation to your stack.
If you lose 75% of a 5K stack, leaving you with 1,250 in chips, but blinds are only 15/30, you still have over 40 BBs to play with. You still have plenty of BBs to play with and don't have to make any rash decisions like shoving your next hand to get back what you lost.
This is a lot different if it were the same scenario, but blinds are at 75/150. Now you have just over 8 BBs and are short stacked. You don't have the luxury of folding hands and waiting for a decent hand as you would with 40 BBs, especially if they're antes. If you get a decent hand immediately after, don't be afraid to jam it in. With 8 BBs, your jamming range is pretty wide and with high blinds and antes eating your stack, you can't wait too long.
Another thing to consider is the type of MTT it is: regular, turbo, hyper turbo. In regular 10-12 min blinds, you can fold a number of hands with 40 BBs before you play anything. The same with 8 BBs, though you don't want to folding a lot of hands you might with 40 BBs. For example, you might fold A8s UTG with 40 BB, but shove with 8 BBs. With turbo and hyper turbos, you might want to play more marginal hands with 40 BBs that you usually wouldn't in regular MTTs to combat the fast blinds. This is especially true with 8 BBs as your stack will get eaten fast. In turbos and hypers, I'm probably shoving all Ax hands, any pair, any KXs, K10o+, and any broadway hand, suited or not.
I think keeping calm is a good idea, but a better question to ask yourself is how do you properly adjust this new situation? Analyze your situation; your stack, the blinds, the blind time, and make your decisions based on the information.
For example, after a loss, I might think "I have 25 BBs left, but blinds go up in a minute, so I practically have 20 BBs left. That's still plenty and I'm still in it, but with blinds increasing every 5 minutes, I can't play too tight. I have play a little more aggressively, steal more pots, and look for those double up spots with my big hands if I want to stand a chance at winning this."