[Gives Shiro a look for a moment while he does that, before leaning across to the faucet and wash off at least his palms, where most of the blood had gathered up. And did he just steal the towel from you?]
If I'm getting the shower first, let me do this.
[It's a quiet attempt at compromise - they both need a shower, they'd both insist the other go first and there's no way in hell Keith is leaving Shiro with the blood on his arms and hands a moment longer than he has to.
... Of course, the first thing he does is wipe the clean part of the towel where Shiro got blood on his face from the headache earlier, impossibly gentle. Because he's a fucking sap.]