He believed that their servant was more afraid to leave than to stay.

He had probably taken a look outside and decided that he was safer under the shelter of those three Winchesters (for the weapon of poor Aaron Johnston was still in the possession of his friends).
Long was inclined to ask him to take charge of the extra rifle, and use it in helping to defend themselves; but, recalling the antipathy of the fellow against handling firearms, he decided that he would only throw away his cartridges.
He, therefore, cautioned him to keep out of the reach of any of the missiles that were likely to come flying into the apartment, and urged him, in case he saw any opening, to dart out among the people and do his best to escape.
Professor Grimcke firmly believed that the impending fight would be to the death, and that the only issue would be the slaying of himself and companion.

It was the same danger they had faced many times, with the difference that this was to be the last.
He surveyed his surroundings, like a general making ready to receive the assault of a foe, and die fighting in the last ditch.
There was the door in front and the two windows, through which the attack could be made.

He could cover all three with his repeating rifle, and, when the last struggle came, appeal to his revolver and knife.

He smiled, grimly at the reflection, that he had every ground for believing, that the victory of the Murhapas would prove the most costly they had ever won.