Things like explosive radii and movement speeds are mostly given to the GM in case that level of specificity is useful - "drones move twice as fast as humans" means they can move two rooms if one of their encounter groups is rolled to move, but more importantly it basically means "if you try to run away, they will catch you".
Similarly, explosive radiuses and timings are given in an exact distance for if it's important - does a person fit through this hole? What about a piece of machinery? Can you set the fuse and have it go off before something happens? Often, none of these things will be important - if your player is using a breaching charge to blow open a locked door while not under attack, for example, all you really need to do is say "you're blind for a fraction of a second as your helmet's glass darkens to protect your eyes, and then the door's open".
When I ran this game, I never measured exact distances during combat using 5 foot squares or similar tools, instead in a more abstract theater-of-the-mind method where relevant locations are things like "behind the doorway" or "on the other side of the room".