No understanding. Would the total code look like: on("change:healthbox_1 change:healthbox_2 change:healthbox_3 change:healthbox_4 change:healthbox_5 change:healthbox_6 change:healthbox_7 change:healthbox_8 sheet:opened", function() {
getAttrs(['healthbox_1', 'healthbox_2', 'healthbox_3', 'healthbox_4', 'healthbox_5', 'healthbox_6', 'healthbox_7', 'healthbox_8'], function(values) {
setAttrs({
injury: Math.floor(Math.max.apply(null, Object.values(healthbox_1, healthbox_2, healthbox_3, healthbox_4, healthbox_5, healthbox_6, healthbox_7, healthbox_8)));
});