That seems to make up for how he feels about what you did to the Voth.
( That ( ( seems ( to ( ( make up ) ( for ( how ( he ( feels ( about ( what ( you ( did ( to ( the Voth ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBZ seems) (S (VP (TO to) (VP (VB make) (PRT (RP up)) (PP (IN for) (SBAR (WHADVP (WRB how)) (S (NP (PRP he)) (VP (VBZ feels) (PP (IN about) (SBAR (WHNP (WP what)) (S (NP (PRP you)) (VP (VBD did) (PP (TO to) (NP (DT the) (NNP Voth))))))))))))))) (. .)))
He held his feelings about what happened to the Voth mostly inside. 
( He ( ( ( held ( his feelings ) ) ( about ( what ( ( ( happened ( to ( the Voth ) ) ) mostly ) inside ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD held) (NP (PRP$ his) (NNS feelings)) (PP (IN about) (SBAR (WHNP (WP what)) (S (VP (VBD happened) (PP (TO to) (NP (DT the) (NNP Voth))) (ADVP (RB mostly)) (ADVP (RB inside))))))) (. .)))