How are people using those laser strikes? Or are those environmental strikes from Alien ships or something? Because I see on the loading screens that you can press 3, 5, or 7 to use different support attacks like Laser Beams, call an air raid, etc. And I've been killed a couple of times by reddish/pink laser beams in the Skytop map, but am not sure if it is another player calling it or it's just that alien ship.

It's the 5 killstreak "Orbital Strike".

Yeah I figured that out last night after I already made this post, lol. O.O It's hard to see that "press P for ______" box in the bottom left corner through all the shooting and trying not to get shot, so I never really payed attention to it. But I've used it several times now and understand where it's all coming from now. Thanks!

Killstreaks.