When you're a soldier working on taking down giant, possibly world ending, mechs, you have to stay in shape- which is why David was currently in the makeshift gym in the garage of his and Hal's current hideout doing some warmup stretches to get the blood flowing in his athletic attire, a tank top and training shorts, before starting his usual workout routine, only difference this time was that Snake had an audience;

Hal.

Otacon had asked him if he could come hang out while Snake followed his routine, giving the reason of needing to step away from the computer for a while and wanting to keep David company, which Snake had no issue with- just having Hal promise not to distract him too much with his nerdy ramblings. So there they were, Snake having Otacon stay off to the side and sitting on an old storage crate while he continued to warmup and stretch, lifting his strong arms above his head before bending over to touch the ground with the palms of his hands before maneuvering down to begin a set of pushups- his back straight, muscles flexing, and making it look like nothing, only occasionally letting out a puff of air as he regulated his breathing to maximize his stamina.

As David continued to do his set, his arms pushing him up then letting him back down close to the ground his nose could have touched the concrete, he could feel a pair of eyes on him, but he didn't look up to see if Hal was watching, nor did he slow down.